NEVER CALL AN ALL-IN



This is an old poker addage- You should be the one GOING all in rather than CALLING the All-IN



This holds true for HU, although it depends on stack size and the size of the blinds relative to your and your opponents stacks.



At the start of the match - if you are both similar stacks, never call an ALL-IN unless you are playing an absolute muppet, who is going all in consistantly (In which case wait for an A and call him



MID Match - if you have lets say twice the number of chips, then is it sometimes worth calling the all-in, but you want to be sure you have at least 50% chance of taking him out of the game. As in you are in a flush or straight draw, or have at least 12 outs.



When the blinds start getting 100-200 calling an all-in becomes a slighlty better move if your opponent has less than half your chips. He will be forced to make a play and you may decide to call if you think you have at least one overcard.

There are clearly some hands where you ALWAYS call an ALL-IN, such as AA and KK, however I would be very wary of calling with QQ unless you have at least twice as many chips. Pocket QQ or less are too open to two overcards.

The odds are as follows:

If your opponent has two overcards to your pocket pair then he wins about 45% of the time, which granted still gives you and edge, but it is marginal. You really want to risk all of your chips when you have at least 70% chance of coming out on top.

That is why by all means go all-in with pocket pair QQ, but call an all-in at your peril.